Adult Ventricle Research Articles

Papiloma del plexo coroideo del tercer ventrículo. Descripción de un caso

Choroid plexus papilloma is an uncommon tumour of the central nervous system, accounting for less than 1% of all intracranial neoplasm. The usual locations are the lateral ventricle in infants and children and the fourth ventricle in adults. The third ventricle is a rare location, with few cases reported in the literature. We describe the case of a 3-month-old boy who was admitted to our centre with signs of raised intracranial pressure. Neuroimaging studies showed a third ventricular mass with associated hydrocephalus. The patient underwent complete tumour removal through a transfrontal approach and ventriculo-peritoneal shunt surgery. Postoperative course of the child was uneventful and follow-up magnetic resonance imaging revealed no residual tumour. Histopathology of the resected lesion confirmed the diagnosis of choroid plexus papilloma. We discuss the clinical, radiological and histological features of this infrequent type of tumours.

Sarcoplasmic reticulum Ca2+-ATPase (SERCA) activity during the transition to endothermy in an altricial bird.

Sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) is a transmembrane pump critical to muscle calcium cycling during contraction, and SERCA has also been proposed as the basis for a non-shivering thermogenesis mechanism in birds. Despite its potential importance to both shivering and non-shivering thermogenesis, the activity of this transporter has rarely been studied in altricial birds, and never during the developmental transition from ectothermy to endothermy. Here, we describe SERCA activity in the pectoralis muscle and heart ventricle of red-winged blackbird (Agelaius phoeniceus) nestlings, fledglings and adults. Additionally, using a diet manipulation, we tested the hypothesis that muscle SERCA activity is affected by dietary fatty acid composition, as has been shown in some previous studies. In blackbird hearts, SERCA activity increased throughout development and into adulthood, conspicuously jumping higher just prior to fledging. In pectoralis muscle, SERCA activity increased throughout the nestling period, but then declined after fledging, an effect we attribute to remodeling of the muscle from a primarily heat-generating organ to a primarily force-generating organ. SERCA activity of the pectoralis muscle was correlated with the proportion of linoleic acid in muscle phospholipids when including all ages in the control group. However, in diet-manipulated birds, there was no consistent relationship between SERCA activity and muscle membrane fatty acid composition at any tested age (5-9 days old). It is unclear whether SERCA might be affected by developmental changes in fatty acid composition at younger ages.

Generation of Nppa-tagBFP reporter knock-in mouse line for studying cardiac chamber specification.

Nppa is a cardiac hormone which plays critical roles in regulating salt-water balance. Its expression is restricted to the atria of the healthy post-natal heart. During heart development, spatio-temporal expression of Nppa is dynamically changed within the heart and becomes restricted to the atria upon birth. In contrast to its atrial specific expression after birth, Nppa is re-expressed in the adult ventricles in response to cardiac hypertrophy. To study cardiac chamber specification during development and pathological cardiac remodeling during heart disease, we generated a novel Nppa reporter mouse line by knocking-in a tagBFP reporter cassette into 3'-UTR of the Nppa gene without disrupting the endogenous gene. Our results demonstrated dynamic tagBFP expression in the developing heart, recapitulating the spatiotemporal expression pattern of endogenous Nppa. We also found that Nppa-tagBFP is induced in the ventricle during pathological remodeling. Taken together, Nppa-tagBFP reporter knock-in mouse model described in this article will serve as a valuable tool to study cardiac chamber specification during development as well as pathological cardiac remodeling.

Comparison of Echocardiography and Computed Tomography on Cardiac Wall Thickness and Internal Dimension Size of Left Ventricle in Normal Adults

Comparison of Echocardiography and Computed Tomography on Cardiac Wall Thickness and Internal Dimension Size of Left Ventricle in Normal Adults

Tricusped Annular Plane Systolic Excursion in Children with ASD

Background: the complexity of estimating RV geometry and function was well documented and Tricusped Annular Plane Systolic Excursion (TAPSE) is one of the assessment tools of the right ventricle in adults. Aim Of the work: this study aimed to evaluate right ventricular (RV) function in children with atrial septal defect (ASD) and to determine whether TAPSE is an accurate marker of right ventricular (RV) systolic function in patients with atrial septal defect (ASD). Patients and methods: This retrospective study was conducted on 30 Egyptian children with age ranged from 2 months to 18 years of both sexes and they were categorized into two groups, 20 patients group with ASD and 10 control group; they were referred to Cardiology Unit of Al-Azhar University Hospitals in the period from December 2016 to December 2018. The ethics committee of Faculty of Medicine, Al-Azhar University approved this study after verbal and written consents from the parents of these children. All children were subjected to the clinical history, general examination, local examination, chest radiograph, electrocardiogram (ECG) and transthorathic echocardiography examination. Results: there was statistical significant difference in TAPSE results between ASD and non-ASD children, statistical significant difference in ECG finding between ASD and nonASD children, there was a statistical significant positive correlation between TAPSE and right ventricular fractional area changes (RVFAC) in the control group and a statistical significant negative correlation between TAPSE and left ventricle ejection fraction (LVEF). Conclusion: TAPSE is a good indicator for the right ventricular function in children with ASD and a good predictor for development of complications.

P711Ventricular assist devices for failing systemic right ventricle in adults with prior atrial switch procedure and congenitally corrected transposition of the great arteries:responders vs non responders

P711Ventricular assist devices for failing systemic right ventricle in adults with prior atrial switch procedure and congenitally corrected transposition of the great arteries:responders vs non responders

Evidence of primary cilia in the developing rat heart

BackgroundA transient increase in cytosolic Ca2+ (the “Ca2+ transient”) determines the degree and duration of myocyte force development in the heart. However, we have previously observed that, under the same experimental conditions, the Ca2+ transients from isolated cardiac myocytes are reduced in amplitude in comparison to those from multicellular cardiac preparations. We therefore questioned whether the enzymatic cell isolation procedure might remove structures that modulate intracellular Ca2+ in some way. Primary cilia are found in a diverse range of cell types, and have an abundance of Ca2+-permeable membrane channels that result in Ca2+ influx when activated. Although primary cilia are reportedly ubiquitous, their presence and function in the heart remain controversial. If present, we hypothesized they might provide an additional Ca2+ entry pathway in multicellular cardiac tissue that was lost during cell isolation. The aim of our study was to look for evidence of primary cilia in isolated myocytes and ventricular tissue from rat hearts.MethodsImmunohistochemical techniques were used to identify primary cilia-specific proteins in isolated myocytes from adult rat hearts, and in tissue sections from embryonic, neonatal, young, and adult rat hearts. Either mouse anti-acetylated α-tubulin or rabbit polyclonal ARL13B antibodies were used, counterstained with Hoechst dye. Selected sections were also labelled with markers for other cell types found in the heart and for myocyte F-actin.ResultsNo evidence of primary cilia was found in either tissue sections or isolated myocytes from adult rat ventricles. However, primary cilia were present in tissue sections from embryonic, neonatal (P2) and young (P21 and P28) rat hearts.ConclusionThe lack of primary cilia in adult rat hearts rules out their contribution to myocyte Ca2+ homoeostasis by providing a Ca2+ entry pathway. However, evidence of primary cilia in tissue from embryonic and very young rat hearts suggests they have a role during development.

Hydrogen Sulfide Protects Human Cardiac Fibroblasts Against H2O2-induced Injury Through Regulating Autophagy-Related Proteins

Autophagy, an intracellular bulk degradation process of proteins and organelles, can be induced by myocardial ischemia in the heart. However, the causative role of autophagy in the survival of human cardiac fibroblasts and the underlying mechanisms are incompletely understood. Oxidative stress can induce autophagy in cultured cells upon hydrogen peroxide (H2O2) exposure. Because hydrogen sulfide (H2S) regulates reactive oxygen species (ROS) and apoptosis, we hypothesize that H2S may have a cardioprotective function. To examine our hypothesis, we investigated the regulation of autophagy by the H2S donor sodium hydrosulfide (NaHS), using a cell model of human cardiac fibroblasts from adult ventricles (HCF-av) that suffered from endoplasmic reticulum (ER) stress by H2O2. In the present study, we found that the apoptosis and autophagy were induced along with ER stress by H2O2 in the primary cultured HCF-av cells. In contrast, H2S suppressed HCF-av cell apoptosis and autophagic flux, in part directly by inhibiting ROS production and preserving mitochondrial functions.

Population-based mechanistic modeling allows for quantitative predictions of drug responses across cell types

Quantitative mismatches between human physiology and experimental models can be problematic for the development of effective therapeutics. When the effects of drugs on human adult cardiac electrophysiology are of interest, phenotypic differences with animal cells, and more recently stem cell-derived models, can present serious limitations. We addressed this issue through a combination of mechanistic mathematical modeling and statistical analyses. Physiological metrics were simulated in heterogeneous populations of models describing cardiac myocytes from adult ventricles and those derived from induced pluripotent stem cells (iPSC-CMs). These simulated measures were used to construct a cross-cell type regression model that predicts adult myocyte drug responses from iPSC-CM behaviors. We found that (1) quantitatively accurate predictions of responses to selective or non-selective ion channel blocking drugs could be generated based on iPSC-CM responses under multiple experimental conditions; (2) altering extracellular ion concentrations is an effective experimental perturbation for improving the model’s predictive strength; (3) the method can be extended to predict and contrast drug responses in diseased as well as healthy cells, indicating a broader application of the concept. This cross-cell type model can be of great value in drug development, and the approach, which can be applied to other fields, represents an important strategy for overcoming experimental model limitations.

Population-Based Mechanistic Modeling Allows for Quantitative Predictions of Drug Responses across Cell Types

Quantitative mismatches between human physiology and experimental models can be problematic for the development of effective therapeutics. When the effects of drugs on human adult cardiac electrophysiology are of interest, phenotypic differences with animal cells, and more recently stem cell-derived models, can present serious limitations. We addressed this issue through a combination of mechanistic mathematical modeling and statistical analyses. Physiological metrics were simulated in heterogeneous populations of models describing cardiac myocytes from adult ventricles and induced pluripotent stem cells derived cardiac myocytes (iPSC-CMs). These simulated measures were used to construct a cross-cell type regression model that predicts adult myocyte drug responses from iPSC-CM behaviors. We found that: (1) quantitatively accurate predictions of adult myocyte responses to selective or non-selective ion channel blocking drugs could be generated based on iPSC-CM responses under multiple experimental conditions; (2) altering extracellular ion concentrations is an effective experimental perturbation for improving the model's predictive strength; (3) the method can be extended to predict and contrast drug responses in diseased as well as healthy cells, indicating a broader application of the concept. This cross-cell type model can be of great value for drug development, and the approach, which can be applied to other fields, represents an important strategy for overcoming experimental model limitations.

Real-time three-dimensional echocardiographic left heart parameters in healthy indian adults

ObjectiveCardiac chamber dimensions are race and anthropometry dependent. We determined the age and gender specific 3-Dimensional echocardiographic (3DE) reference values for dimensions and function of left ventricle (LV) and left atrium (LA) in normal Indian adults. MethodsThis single center prospective study enrolled 133 adult Indians free of heart disease and/or hypertensions, subjecting them to 3DE measurements of left atrial (LA) & left ventricular (LV) volumes, function and left ventricular mass (LVM). The higher limits of normal cut-offs were determined for these parameters and their dependency on age, gender and anthropometry were analyzed. ResultsThe body surface area (BSA) corrected higher limit cut-offs were: 59.37ml/m2 for LV end diastolic volume (59.19ml/m2 and 59.61ml/m2 for men and women, respectively; P=NS); 23.48ml/m2 for LV end systolic volume (23.27ml/m2 and 23.11ml/m2 for men and women, P=NS). Mean LVEF was 64.79%±7.26 (62.99%±6.51 and 67.05%±7.58 in men and women, P=NS). Men had higher LVM than women (119.79g±23.95 vs. 103.26g±23.76, P<0.001), this difference disappeared after BSA indexing. The higher limit cut-offs for normal LA volumes were 20.49ml for minimum volume (21.18ml and 19.46ml for men and women, P=NS) and 39.76ml for maximum volume (39.60ml and 40.03ml in men and women, P=NS). The parameters were smaller compared to western populations but the differences attenuated after BSA indexing. ConclusionsThe study reports normal 3DE parameters of size and function of left heart chambers in Indians.

Uncommon presentation of an uncommon disorder – A case series of double chambered right ventricle in adults

Uncommon presentation of an uncommon disorder – A case series of double chambered right ventricle in adults

Evaluation of spatial and temporal relationship between left ventricular volume and longitudinal strain in healthy subjects by 2D speckle-tracking echocardiography

Objective To evaluate the coupling relationship between segmental longitudinal strain and left ventricular volume at different phases of the cardiac cycle by two dimensional speckle tracking imaging. Methods 2D grey scale images of 41 healthy adults were acquired, and time curve of left ventricular volume (LVV), segmental longitudinal strain (LS) and segmental longitudinal strain rate (LSr) were outputed by analysis software. The correlations between LVV and LS or LSr in isovolumic relaxation time(IVRT), the rapid filling time(RFT), the atrial filling time(AFT) and the ejection time(ET) were analyzed respectively. Results ①IVRT: LS in basal segment, middle segment, apical segment of interventricular septum, in apical segment, basal segment of the lateral wall, and in middle segment of inferior wall were low-moderate negatively correlated with LVV; only LSr in middle segment of anterior wall was negatively correlated with LVV (P<0.05). ② RFT: LS in middle segment, apical segment of interventricular septum, in apical segment of the lateral wall were negatively correlated with LVV; LSr in basal segment, middle segment, apical segment of interventricular septum, in apical segment, middle segment, basal segment of lateral wall, in middle segment, basal segment of inferior wall were low-moderate negatively correlated with LVV (P<0.05). ③AFT: LS in basal segment of inferior wall, in apical segment, basal segment of the anterior wall were low negatively correlated wtih LVV (P<0.05). ④ET: LS in basal segment, middle segment, apical segment of interventricular septum, in apical segment, basal segment of the lateral wall were low negatively correlated with LVV (P<0.05); only LSr in apical segment of lateral wall was negatively correlated with LVV (P<0.05). Conclusions LS or LSr in special segments of interventricular septum, lateral wall, anterior wall and posterior wall are actively participate in the volume change of the left ventricle in healthy adults, specific myocardial segments of left ventricular wall are involved in left ventricular volume changes. Key words: Echocardiography; Ventricular function, left; Left ventricular volume; Longitudinal strain; Speckle tracking imaging

Transient Notch Activation Induces Long-Term Gene Expression Changes Leading to Sick Sinus Syndrome in Mice.

Notch signaling programs cardiac conduction during development, and in the adult ventricle, injury-induced Notch reactivation initiates global transcriptional and epigenetic changes. To determine whether Notch reactivation may stably alter atrial ion channel gene expression and arrhythmia inducibility. To model an injury response and determine the effects of Notch signaling on atrial electrophysiology, we transiently activate Notch signaling within adult myocardium using a doxycycline-inducible genetic system (inducible Notch intracellular domain [iNICD]). Significant heart rate slowing and frequent sinus pauses are observed in iNICD mice when compared with controls. iNICD mice have structurally normal atria and preserved sinus node architecture, but expression of key transcriptional regulators of sinus node and atrial conduction, including Nkx2-5 (NK2 homeobox 5), Tbx3, and Tbx5 are dysregulated. To determine whether the induced electrical changes are stable, we transiently activated Notch followed by a prolonged washout period and observed that, in addition to decreased heart rate, atrial conduction velocity is persistently slower than control. Consistent with conduction slowing, genes encoding molecular determinants of atrial conduction velocity, including Scn5a (Nav1.5) and Gja5 (connexin 40), are persistently downregulated long after a transient Notch pulse. Consistent with the reduction in Scn5a transcript, Notch induces global changes in the atrial action potential, including a reduced dVm/dtmax. In addition, programmed electrical stimulation near the murine pulmonary vein demonstrates increased susceptibility to atrial arrhythmias in mice where Notch has been transiently activated. Taken together, these results suggest that transient Notch activation persistently alters ion channel gene expression and atrial electrophysiology and predisposes to an arrhythmogenic substrate. Our data provide evidence that Notch signaling regulates transcription factor and ion channel gene expression within adult atrial myocardium. Notch reactivation induces electrical changes, resulting in sinus bradycardia, sinus pauses, and a susceptibility to atrial arrhythmias, which contribute to a phenotype resembling sick sinus syndrome.

Characterization of left ventricle energy loss in healthy adults using vector flow mapping: Preliminary results.

Energy loss (EL) is a new quantitative hemodynamic index based on vector flow mapping (VFM). This study aimed to characterize EL of the left ventricle (LV) in healthy adults. Fifty-one healthy adults were enrolled in this study. EL of LV was analyzed frame by frame using color Doppler images of a standard apical three-chamber dynamic view on an offline VFM workstation. The average EL of systole and diastole was calculated, and the results were averaged over three cardiac cycles. The average EL for systole and diastole was 11.07±5.82J/m/s and 11.58±5.54J/m/s, respectively. Multivariate regression analysis showed that the aortic velocity time integral (AOVTI), A-wave peak velocity, and isovolumetric contraction time (IVCT) were independently associated with the average systolic EL. E-wave peak velocity, height, and IVCT were independently associated with the average diastolic EL. For females, the average systolic and diastolic EL was 12.66±7.06J/m/s and 13.90±5.37J/m/s, respectively. For males, the systolic and diastolic EL was 9.29±3.33J/m/s and 8.97±4.55J/m/s, respectively. Energy loss in LV changes regularly during the cardiac cycle. The average systolic EL has a high positive correlation with AOVTI, whereas the average diastolic EL has with E-wave peak velocity. Women have higher average EL than men in both systole and diastole. By recognizing the EL characterization of healthy adults, the variation in EL may reflect cardiac dysfunction. These were preliminary results, and thus, the clinical implications of EL warrant further investigation.

Aortopathy in adults with tetralogy of Fallot has a negative impact on the left ventricle

BackgroundAortic pressure wave reflection is significantly elevated in patients with congenital heart disease, even in children. Excessive aortic pressure wave reflection provokes cardiovascular events. AimTo assess the influences of the enhanced pressure wave reflection on the left ventricle (LV) in adults with repaired tetralogy of Fallot (TOF). MethodsProspectively, 51 consecutive adults with repaired TOF (35.5±11.6yrs., 25 males) were enrolled and non-invasively assessed the pressure wave reflection using HEM 9000AI. A surrogate maker of the aortic pressure wave reflection, radial augmentation index (rAI) was calculated as reflection wave divided by ejection wave. We also evaluated LV function using echocardiography and magnetic resonance images. Patients were divided into two groups: group A with rAI≧1SD and group B with rAI<1SD. ResultsThe mean rAI in repaired TOF was 76.9±14.3%. In group A, indexed ascending aortic diameter, LV global longitudinal strain (GLS), LV global circumferential strain (GCS), LV early diastolic strain rate (SR), LV E/A, LV e′ were significantly higher than them in group B. The indexed ascending aortic diameter significantly correlated with rAI (r=0.31, P<0.05). On univariate logistic analysis, body surface area, indexed ascending aortic diameter, GLS, GCS, early diastolic SR, LV E/A, LV mass index and creatinine were predictive factors of rAI≧1SD. On multivariate logistic analysis, LV E/A was the most significant predictive factor of rAI≧1SD (Odds ratio 0.044, 95%CI 0.002–0.98 and P<0.05). ConclusionsAortic pressure wave reflection in adults with repaired TOF has a negative impact on LV function, particularly on diastolic function.

Abstract 11413: Appearance of QRS Fragmentation Late After Atrial Switch Repair for d-Transposition of the Great Arteries is Associated With Adverse Clinical Outcome

Introduction: The extent of myocardial fibrosis on magnetic resonance imaging (MRI) in the systemic right ventricle (RV) of adults after atrial switch repair for d-transposition of the great arteries (d-TGA) correlates with outcome. However, MRI is costly and access is limited. Fragmented QRS (fQRS) on a 12-lead electrocardiogram (ECG) reflects inhomogeneous ventricular activation. It is considered to be a surrogate for fibrosis and related with outcome in ischemic cardiomyopathy. Hypothesis: Appearance of fQRS during follow-up is a predictor for adverse events in adults after atrial switch repair for d-TGA. Methods: Records of adults with atrial switch repair for d-TGA were retrospectively reviewed in the database of a tertiary care hospital. Exclusion criteria were systemic RV assist device or heart transplantation (HTx) before the age of 16 years, or fQRS already present at transfer from the pediatric department. One blinded reader analyzed all available ECGs to detect fQRS. fQRS, severe tricuspid regurgitation (TR), severe RV dysfunction and severe RV dilatation were modeled as time-dependent covariates. Cox regression was performed to assess the relationship between covariates and (1) the composite endpoint of cardiovascular mortality, HTx or systemic RV assist device, and (2) worsening RV function. Results: Records of 89 patients (34% female, 42% Mustard repair) were analyzed. Patients underwent atrial switch repair between Oct 1969 and Nov 1992. At latest follow-up, fQRS was noted in 26 patients (29%), most frequently inferior (92%). Over a median follow-up of 16.9 (IQR 12.6-22.9) years, the composite endpoint occurred in 9 patients (10%). In multivariate Cox analysis, appearance of fQRS (HR 14.11; 95% CI 1.42-140.12) and development of severe RV dysfunction (HR 11.36; 95% CI 2.08-62.17) were significantly associated with the composite endpoint. Moreover, appearance of fQRS was significantly associated with worsening RV function (HR 2.66; 95% CI 1.18-6.01), independently of development of severe TR. Conclusions: Appearance of fQRS is associated with adverse clinical outcome and worsening RV function in adults after atrial switch repair for d-TGA. It might become an easily implementable tool to identify patients at risk for adverse events.

Notch signalling in ventricular chamber development and cardiomyopathy.

The vertebrate heart is the first organ to form and function during embryogenesis. Primitive streak-derived cardiac progenitors located bilaterally move rostral to form the primitive heart tube that subsequently undergoes rightward looping, remodelling and septation to give rise to the mature four-chambered heart. Tightly regulated tissue interactions orchestrate the patterning, proliferation and differentiation processes that give rise to the adult ventricles. Studies in animal models have demonstrated the crucial function of the Notch signalling pathway in ventricular development and how alterations in human NOTCH signalling may lead to disease in the form of cardiomyopathies, such as left ventricular noncompaction (LVNC). In this review, we discuss how during trabecular formation and ventricular compaction, Dll4-Notch1 signals from chamber endocardium to regulate cardiomyocyte proliferation and differentiation in a noncell autonomous fashion and how, at later stages, myocardial Jag1 and Jag2 activate Notch1 in chamber endocardium to sustain chamber patterning and compaction with simultaneous coronary vessel development mediated by Dll4-Notch1. We suggest that alterations in these molecular mechanisms underlie MIB1-related familial LVNC and favour the hypothesis that this cardiomyopathy has a congenital nature.

Electrophysiological Properties of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes Cultured on a Flexible Matrigel Substrate

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) provide a unique tool to evaluate cellular properties in disease models, investigate underlying mechanisms and optimize cell-based therapies. We recently reported that after plating 30 day old single hiPSC-CMs on undiluted Matrigel “Mattress” (thickness ∼0.5 mm) for 5 days, mattress hiPSC-CMs developed a rod-like cell shape, aligned myofilament structure, increased sarcomere length and exhibited robust cell shortening. Here, we compared the electrophysiological properties of mattress hiPSC-CMs to hiPSC-CMs cultured on standard substrates (control) and acutely-isolated adult rabbit CMs. The action potentials of mattress hiPSC-CMs were comparable to rabbit CMs. Compared to control, mattress hiPSC-CMs had significantly increased the action potential upstroke velocity due to two-fold increase in sodium current (INa) (−68.61±11.63 pA·pF-1 in mattress vs. −29.66±7.50 pA·pF-1 in control at −30mV). The inward rectifier current (IK1) is responsible for the maintenance of resting membrane potential and contributes to phase 3 of the action potential. Although resting potential and action potential duration was not different from rabbit CMs, IK1 density in mattress hiPSC-CMs was nine-time smaller than in rabbit CMs, but there was no difference between mattress and control hiPSC-CMs (−4.86±0.66 pA·pF-1 in mattress vs. −43.75±4.13 pA·pF-1 in rabbit vs. −3.98±0.83 pA·pF-1 in control at −120 mV). The funny current (If) is an inward current activating at hyperpolarized membrane potential, which is detectable in the developing heart but absent in the adult ventricle and contributes to the spontaneous beating of hiPSC-CMs. Mattress hiPSC-CMs exhibit robust If that was not significantly different from control (−6.22±1.31 pA·pF-1 in mattress vs.-5.60±1.43 pA·pF-1 in control at −120 mV). In summary, the matrigel mattress method enables the rapid generation of robustly contracting single hiPSC-CMs and increases INa, with negligible effect on IK1 or If.

Rapid Fire Abstract session: assessing the single ventricule and new techniques for assessing tetralogy477Echocardiographic assessment of ventricular function and predictors of mortality in adults with a Fontan circulation478The left pulmonary artery doppler in the assessment of atrial restriction after the hybrid procedure for hypoplastic left heart syndrome479Magnetic resonance imaging in patients with Fontan physiology detects a high prevalence of liver

Rapid Fire Abstract session: assessing the single ventricule and new techniques for assessing tetralogy477Echocardiographic assessment of ventricular function and predictors of mortality in adults with a Fontan circulation478The left pulmonary artery doppler in the assessment of atrial restriction after the hybrid procedure for hypoplastic left heart syndrome479Magnetic resonance imaging in patients with Fontan physiology detects a high prevalence of liver